Crystal growth of Ca-doped PrBa₂Cu₃O_7-delta (Pr-123) single crystals by slow cooling of Pr₃O₁₁-CaCO₃-BaCO₃-CuO melts (self-flux technique) in ambient air atmosphere was studied. As the first approach the growth of Ca-free crystals in Al₂O₃ and ZrO₂ crucibles was investigated. The best quality crystals with the average size of 5 x 5 x 0.2mm³ were obtained from Al₂O₃ crucibles for Ba/Cu = 0.41 and 15 wt.% (2.41 mol.%) of stoichiometric Pr-123 solute in the melt. Next, using CaCO₃ as calcium source (0.09 -12.68 wt.%), the good quality Pr_1-xCa_xBa₂Cu₃O_7-delta crystals with 0 <= x <= 0.26 were grown in the Al₂O₃ crucibles from the solution with fixed value of Ba/Cu = 0.41. The oxygenated single crystals with size up to 5 x 8 x 0.2 mm³ were used for electric transport investigations from four-probe resistivity measurements. The temperature dependence of resistivity of Ca-doped Pr-123 crystals is typical for systems with locallized states and, in principle, follows the Mott law for variable-range hopping (VRH).

Keywords: PrBaCuO, single crystals, calcium doping, hole doping, hopping, superconductivity

---

The full text of this paper in pdf-Format:

If you came directly to this page, click this symbol to go to the homepage of CRT.